1. Field of the Invention
This invention relates broadly to surgery. More particularly, this invention relates to surgical meshes for the repair of hernia.
2. State of the Art
Hernias are caused by abnormal defects, tears, or natural openings in membranes, layers of muscle, and/or bone in the body. Such defects may weaken the structural integrity of the defect area and can permit migration of adjacent body structures and/or surrounding tissue (e.g., through an opening), which can result in serious and quite painful symptoms. An inguinal hernia is a protrusion of the abdominal-cavity contents through the inguinal canal and, on each of lateral and contralateral sides of the body, is generally classified as either a direct or indirect hernia defined by its relationship to the inferior epigastric vessels. Direct inguinal hernias occur medial to the inferior epigastric vessels when abdominal contents herniate through a weak spot in the fascia of the posterior wall of the inguinal canal, which is formed by the transversalis fascia. Indirect inguinal hernias occur when abdominal contents protrude through the deep internal ring, lateral to the inferior epigastric vessels. Pantaloon hernias require repair over both the direct and indirect sides.
There are various surgical strategies which are considered in the planning of inguinal hernia repair. Amongst other considerations are mesh use; i.e., whether the biologic tissue will be repaired only to itself or whether a synthetic mesh will be used to assist the repair, and whether the repair will be via an open technique or a closed through-port laparoscopic procedure.
Historically, hernias have been treated by creating an incision through the abdominal wall in an open technique and retracting layers of healthy tissue to expose the defect. The defect was often repaired by sewing strong surrounding muscle over the defect.
Now, with an open technique, it is more common for the surgical repair to be performed in conjunction with a biocompatible mesh that is surgically placed between the layers of tissue at the defect and used to help restore the structural integrity of the repair site. Various types of meshes have been used. Initial biocompatible meshes were flat sheets that were placed at the defect. More recent hernia repair meshes have included additional structure to ostensible aid in the repair.
U.S. Pat. No. 6,565,580 to Beretta teaches a multilayer mesh in which the layers are connected by a flexible band. The lower layer is provided with a hole. In the open technique, which is performed from the outside, the hole was a necessary feature to accommodate the spermatic cord.
U.S. Pat. No. 6,740,122 to Pajotin teaches a mesh with a uniformly stiff three dimensional bowl-shaped structure that conforms to the anatomical shape of the defective wall as presented during an open technique repair. While surgeon's use a commercial embodiment of such mesh in both an open and laparoscopic repair, as a result of the stiffness and shape, the lower border has a tendency to fold up during the laparoscopic repair. This can result in a portion of the defect remaining unsupported. At an unsupported location there is an inherent risk for hernia recurrence.
More recently, it has been preferred by many surgeons to approach the inguinal repair of hernia through a laparoscopic procedure. However, in a laparoscopic repair, the surgery is performed through ports inserted through the abdominal cavity in order to approach the hernia from the interior (opposite) side of the subject anatomy. The mesh is rolled into a tubular form and inserted through a port to the site of the defect. Once the mesh is positioned for repair, it is necessary to retain the mesh so as to prevent displacement and patient discomfort. However, currently available meshes are not ideally adapted for retention on the anatomy from the laparoscopic approach.